Review of Classification for Wall Climbing Robots for Industrial Inspection Applications

A new methodology that mixes the already well-established classifications of Wall Climbing Robots (WCR) based on locomotion and attachment is proposed. The need for industrial inspections of processing assets, with vertical flat surfaces, like tanks and pressure vessels that are continuously exposed to fatigue, corrosion and erosion are identified. The types of industrial inspections tasks vary in a wide range from, Visual Inspections (VI) and Non-Destructive Testing (NDT) to cleaning and repair. Mobile robots are used to perform inspection tasks. There are few commercial WCR that are available for industrial applications. The classification method is based on locomotion mechanisms, and attachment techniques rather than classical classification assumed in all previous reviews of WCR. A general design framework is suggested to derive the custom-building design of the inspection WCR. The performance of the WCR is compared against the main features of maximum speed and payload capacity. The main locomotion types are wheeled (W), tracked (T), walking (L) and hybrid (H). The primary attachment methods are magnetic (G), pneumatic (P), mechanical (M), electrostatic (E), chemical (C) and hybrid (H). As another application, the classification is used to identify and differentiate WCR from other types of Climbing Robots (CR) to cover almost all kinds of WCR. In addition, the classification can be employed in the customisation of WCR that are built to perform specialised inspection tasks. The customisation of WCR results from the need for simplicity in their structure, adapting testing equipment and improving operations.